Folding square



(No Model.) A

A. G. MCDONALD.

FOLDING SQUARE. No. 534,246. Patented Feb. 12, 1895.

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UNITED STATES PATENT OFFICE.

ANGUS G. MCDONALD, OF ARLINGTON, MASSACHUSETTS.

FOLDING SQUARE.

SPECIFICATION forming part of Letters Patent No. 534,246, dated February 12, 1895.

Application filed May 1'7, 1894. Serial No. 511,628.y (No model.)

To all whom, it may concern: v

Be it known that I, ANGUS G. MCDONALD, a subject of the Queen of Great Britain, residing at Arlington, in the county of Middlesex and State of Massachusetts, have invented a certain new, useful, and valuable Improvement in Folding Squares, of which the'following is a full, clear, and exact description. My present invention relates to folding squares and has for its object to provide a square of economical and practical construction which is adapted to be folded into a comparatively small space and which when set for use is as rigid and accurate as a solider ordinary square. y Figure l shows my improved square as set for use. Fig. 2 shows the same folded. Fig. 3 is a sectional view through line 3-3 of Fig. 2.

Similar characters of reference indicate like parts throughout the several views.

The short arm A and long arm B are pivotally connected at the point A', and the rightangle piece C is pivotally connected to the short arm A at the point A2. At the upper part of long arm B a notch B' is provided and above this notch the arm is narrower, so that when the arms are set at right angles to each other and the right-angle piece C locks them in position as shown at Fig. 1, the outer edges of the right-angle piece forms a perfect line with the outer edges of the two arms. The tongue C' setting into the notch B' is ordinarily sufficient to hold the arms rigidly in position, but in order to make them more secure I may employ a screw B2 which prevents the angle-piece C from getting out of position. I may also provide a tongue C2 which fits into a corresponding groove in the long arm B and serves to keep the surfaces of the several parts perfectly true or flat.

Having described my invention, what I claim is` l. In a folding square, the combination with the short arm A, of the long arm B, pivotally connected to said short arm and having its outer face out away opposite its point of pivotal connection, said out away part terminating in a notch B', and an angle piece C, pivoted to the outer face of said short arm and provided with an enlargement C', said angle piece serving to form the angle of the square and to lock the parts in position when open for use, substantially as described.

2. In a folding square, the combination with the short arm A, of the long arm B, pivoted to said short arm, and having a portion of its outer face out away and provided with a notch B', the pivoted end of said long arm being rounded off and provided with a groove, an angular piece C pivoted to said short arm and provided with an enlargement C' and having a tongue upon its inner edge engaging with the groove at the end of the long arm, said piece C serving to form the angle of the square and to lock the two arms together when opened at a right angle to each other, substantially as described.

In testimony whereof I affix my signature in presence of two witnesses.

ANGUS G. MODONALD. Witnesses:

ADAM WALKER, JAMES CRAMOND. 

